祁连山北缘冲断带西段构造特征

Structural character of western part of northern Qilian Mountain front thrust belt

祁连山北缘冲断带是中国较早发现油田的地区之一,近几年来该区油气勘探又获得进一步突破。文中根据近几年得到的地震、钻井、地面露头资料,结合前人研究成果,分析了祁连山北缘冲断带西段的构造特征。祁连山北缘冲断带具有中国西部山前冲断带的共同特征:构造主要定型于喜山期;断层相关褶皱、冲断构造体系发育;冲断带分段分带明显;构造复杂。除此之外,祁连山北缘冲断带西段也有独特的构造特征。由于不同性质盆地的叠合,冲断带走向方向地层组成变化大;冲断带的分段性受控于古构造格局;主要发育横向叠置的多重冲断构造体系。这些特征造成了北缘冲断带油气勘探的复杂性。

The Northern Qilian Mt. front-fold-thrust belt is one of the regions where oil fields were first discovered in China. Recent years exploration and research have resulted in new achievements. By integrating seismic data, well-log, and field observations with the findings of previous research, the authors analyse the structural character of the western part of Qilian Mt. front thrust belt. Some of the main features of the Qilian belt are similar to those in western China, such as fault-related folds and thrust systems developed in thrust belts, which formed during the Himalayan orogenesis. But some are distinctive, strata constituent in the belt varies in the direction of system extend, and paleo-structure dominated the zonation of thrust belt, and thrust structural system superposed laterally ,which all resulted from superposition of various types of basins developed in different time.